A high pressure natural gas tank or a high pressure hydrogen tank is used as a supply source of a fuel gas in an internal combustion engine mounted on a natural gas vehicle or in a fuel cell system mounted on a fuel cell vehicle. A known method of manufacturing such a high pressure tank is a manufacturing method using filament winding method (hereinafter may be simply referred to as “FW method”). The method of manufacturing the high pressure, tank by the FW method winds a reinforced fiber impregnated with a thermosetting resin such as an epoxy resin on the outer periphery of a liner and heats and thermally cures the thermosetting resin to form a fiber-reinforced resin layer.
As is known, the manufacturing method using the FW method provides self-heating of the thermosetting resin during heating. A known technique takes advantage of such self-heating to increase the efficiency of the heat curing process. There is, however, a problem that a temperature rise beyond expectation causes thermal degradation of the liner at a peak of self-heating of the thermosetting resin. Patent Literature 1 describes a method of manufacturing a tank that uses a heat insulating material to cover the outer circumferential surface of a liner and thereby suppresses thermal degradation. Patent Literature 2 describes a method of manufacturing a composite container that divides a heating process of a thermosetting resin into a step of decreasing the viscosity of the resin and a step of thermally curing the resin.